From 3f5af3f71195b7f1ebe32bd0d695b59904fff778 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Thu, 16 Apr 2020 16:45:15 -0400 Subject: [PATCH] c++: Hard error with tentative parse of declaration [PR88754] In the testcase for this PR, we try to parse the statement A(value<0>()); first tentatively as a declaration (with a parenthesized declarator), and during this tentative parse we end up issuing a hard error from cp_parser_check_template_parameters about its invalidness as a declaration. Rather than issuing a hard error, it seems we should instead simulate an error since we're parsing tentatively. This would then allow cp_parser_statement to recover and successfully parse the statement as an expression-statement instead. gcc/cp/ChangeLog: PR c++/88754 * parser.c (cp_parser_check_template_parameters): Before issuing a hard error, first try simulating an error instead. gcc/testsuite/ChangeLog: PR c++/88754 * g++.dg/parse/ambig10.C: New test. --- gcc/cp/ChangeLog | 6 ++++++ gcc/cp/parser.c | 4 ++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/g++.dg/parse/ambig10.C | 20 ++++++++++++++++++++ 4 files changed, 35 insertions(+) create mode 100644 gcc/testsuite/g++.dg/parse/ambig10.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 8410ff1d1cb..465f29090f4 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2020-04-17 Patrick Palka + + PR c++/88754 + * parser.c (cp_parser_check_template_parameters): Before issuing a hard + error, first try simulating an error instead. + 2020-04-17 Jakub Jelinek PR other/94629 diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index 7be4a8f5cbd..d2f3f853cb4 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -28530,6 +28530,10 @@ cp_parser_check_template_parameters (cp_parser* parser, if (!template_id_p && parser->num_template_parameter_lists == num_templates + 1) return true; + + if (cp_parser_simulate_error (parser)) + return false; + /* If there are more template classes than parameter lists, we have something like: diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 15f5cb2a633..b80e7da1c82 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-04-17 Patrick Palka + + PR c++/88754 + * g++.dg/parse/ambig10.C: New test. + 2020-04-17 Thomas Koenig PR fortran/94090 diff --git a/gcc/testsuite/g++.dg/parse/ambig10.C b/gcc/testsuite/g++.dg/parse/ambig10.C new file mode 100644 index 00000000000..42b04b16923 --- /dev/null +++ b/gcc/testsuite/g++.dg/parse/ambig10.C @@ -0,0 +1,20 @@ +// PR c++/88754 +// { dg-do compile } + +struct A +{ + A(int); + void foo(); +}; + +template int value() { return N; } + +void bar() +{ + A(value<0>()).foo(); + A(value<0>()); + (A(value<0>())).foo(); + + A value<0>; // { dg-error "invalid declaration" } + A value<0>(); // { dg-error "invalid declaration" } +} -- 2.30.2